Technical Fields
The disclosure relates to a control device and a control method.
Priority is claimed on Japanese Patent Application No. 2015-185017, filed Sep. 18, 2015, the contents of which are incorporated herein by reference.
Related Art
In a plant and a factory (hereinafter, called simply “plant” as a generic name of them), a process control system is established, and an advanced automatic operation is implemented. The process control system controls various types of state quantity (for example, pressure, temperature, flow quantity) in an industrial process. In order to secure safety and perform an advanced control, the process control system is equipped with a control system such as a distributed control system (DCS) and a safety system such as a safety instrumented system (SIS).
In the distributed control system, field devices (for example, a measurement device and a manipulation device) and a control device controlling the field devices are connected to each other through communication means. In the distributed control system, the control device collects measurement data measured by the field devices, and the control device operates (controls) the field devices in accordance with the collected measurement data, in order to control various types of state quantity. In an emergency, the safety instrumented system stops the plant certainly in a safe state. Thereby, physical injury and environmental pollution are prevented beforehand, and expensive facilities are protected.
In the conventional safety instrumented system, field devices which detect gas, flame, heat, smoke are prepared, and an alarm is output in accordance with a detection result of the field device. For example, a fire detecting system which is equipped with a carbon monoxide detector is disclosed in U.S. Pat. No. 8,354,935. If a level of the carbon monoxide measured by the carbon monoxide detector exceeds a threshold value, an alarm is output to an alarm panel.
High reliance and stable operation are required for the distributed control system and the safety instrumented system in order to secure safety of the plant. Therefore, high reliability and high maintainability are required for a program (application logic) which runs on the control device. For this reason, it is not preferable that proven application logic is changed greatly. In some industries or companies, a rule (policy) of programming is often made formally or implicitly.
On the other hand, with respect to hardware such as an interface module and a field device, new parts are adopted in accordance with technical progress, parts are discontinued, and parts are changed in accordance with cost reduction demands, in many cases. For this reason, in the conventional control device, it is necessary that the application logic is changed greatly in accordance with a change of hardware. Otherwise, it is necessary that a part of an improvement effect by the change of the hardware is given up, and a change range of the application logic is reduced.